Speed controller with scales

ABSTRACT

A speed controller with scales according to the invention is used to adjust the amount of an air flow thereby to control the amount of a chemical liquid sprayed. The speed controller includes a housing, a controller body and a transparent tube. The controller body is partly inserted in the housing and has a rotary button located at one end thereof and outside the housing. The rotary button has a slot and an indicator thereon, wherein the indicator is located at one end of the slot. The transparent tube, having a vertical scale on the side thereof and a circular scale on the top circumference thereof, encloses the rotary button. In the invention, the position of the rotary button can be determined by reading the vertical scale and the circular scale so as to precisely control the amount of a chemical liquid sprayed, thereby increasing yield and improving engineering analysis.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a speed controller (SC), and in particular to aspeed controller with scales by which the position of a rotary buttonthereof can be determined.

2. Description of the Related Art

In line with higher integration of IC devices, the accuracy of thesemiconductor process apparently becomes more important. Once any tinyerror occurs in the semiconductor process, it causes a failure to theentire process, resulting in wafer damaging or scraping. Therefore, agreat amount of cost is consumed.

Photolithography is one of the most important steps in the entiresemiconductor process. Any regions, related to the structure of MOStransistors, for subsequent patterning and doping, are defined byphotolithography. Basically, the photolithography includes three stepsof coating, exposing and developing.

As to the coating, if a photoresist liquid is not uniformly sprayed ontoa wafer, it can cause a failure to the entire semiconductor process.

Referring now to FIG. 1, there is shown a photoresist spray system. Whencoating a photoresist on a wafer, a photoresist liquid is evacuated froma photoresist bottle 10 via a filter 14 to spray onto a wafer 16 by apump 12, wherein the filer 14 is used to filter the photoresist liquid.Furthermore, at least one speed controller 18, which is connected to thepump 12, can be adjusted to control the amount of the photoresist liquidsprayed. The performance of the entire photoresist spray system hingeson the capability of the speed controller 18.

Next, referring to FIG. 2, a speed controller according to the prior artis shown. The speed controller is an SMC 1200 series speed controller oran SMC 1400 series speed controller.

In FIG. 2, the speed controller 18 includes a housing 22 and acontroller body 20 which is partly inserted in the housing 22. Inaddition, the controller body 20 has a rotary button 24 at one endthereof and a fixing button 26 under the rotary button 20. The rotarybutton 24 has stripes thereon which are designed to facilitate adjustingthe amount of an air flow in the pump 12. The fixing button 26 is usedto lock the rotary button 24 thereby to prevent unintentionaladjustments.

As to the photoresist spray system, the amount of a photoresist liquidsprayed is one of main check items. For example, how many milliliterscan be sprayed out in several seconds. In practice, it is found that theamount of photoresist liquid sprayed is inversely proportional to usetime. This results from the filter 12 congested by photoresistparticles. When the decrease in the amount of the photoresist liquidsprayed is found, an operator must adjust the speed controller 28 toallow the pump 12 to evacuate more amount of the photoresist liquid forcompensation.

Assume that the photoresist spray system is installed with a new filter14. Since the filer 14 is not congested by photoresist particles at all,a required amount of photoresist liquid sprayed can be easily obtainedby just adjusting the speed controller 18 to a lower position. However,several weeks or months later, the speed controller 18 must be adjustedto a higher position for obtain the required amount of the photoresistliquid sprayed.

According to the prior speed controller 18, there is no way to predictthe extent of the filter 14 congested. In general, the filer 14 isreplaced with a new one by time, for example, once two months,regardless whether the filer 14 is still functional or not. As a result,it is possible that the filter 14, which cannot function well any more,is still used before the time for replacement, leading to a failure.This may be caused by an extra processing to have the filter 14seriously congested or the unclean photoresist bottle 16 havingcongealed photoresist therein. Thus, a photoresist is poorly formed onthe wafer 16.

Furthermore, the prior speed controller shown in FIG. 2 has no scalesdesigned thereon. Therefore, an operator adjusts the speed controlleronly based on operating results. It seems reasonable to be widely usedin the semiconductor process. However, there are disadvantages asfollows.

(1) The speed controller is lack of previous alarm. If the system isalready regulated, the speed controller should be adjusted within acertain range, so that the same results can be obtained under the sameconditions. However, if the speed controller is abnormally adjusted,this implies that the system encounters a serous failure somewhere.Since no scales are designed on current-used speed controllers made byvarious manufacturers, the above-stated problem cannot be previouslydiscovered and resolved.

(2) If the speed controller is adjusted only based on operating results,it seems to take the materials and products as experiments, resulting inthe increase of manufacturing costs. An operator learns the speedcontroller should be adjusted only when failures are encountered. Thisis obviously unreasonable.

(3) The speed controller cannot be precisely adjusted.

(4) It is not convenient for engineering analysis.

SUMMARY OF THE INVENTION

In view of the above, a first object of the invention is to provide aspeed controller with scales for resolving the problem of being lack ofprevious alarm stated in the prior art.

A second object of the invention is to provide a speed controller withscales for a more precise control and adjustment, thereby increasingyield.

To obtain the above-mentioned objects, a speed controller with scalesaccording to the invention, suitable for adjusting the amount of an airflow thereby to control the amount of a chemical liquid sprayed,includes a housing, a controller body and a transparent tube. Thecontroller body is partly inserted in the housing and has a rotarybutton located at one end thereof and outside the housing. The rotarybutton has a slot and an indicator thereon, wherein the indicator islocated at one end of the slot. The transparent tube, having a verticalscale on the side thereof and a circular scale on the top circumferencethereof, encloses the rotary button.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings, which aregiven by way of illustration only, and thus do not limit the presentinvention, and wherein:

FIG. 1 is a block diagram showing a photoresist spray system;

FIG. 2 is a perspective view showing a speed controller according to theprior art;

FIG. 3 is a perspective view showing a speed controller according to apreferred embodiment of the invention;

FIG. 4 is a magnified view showing the top surface of a rotary button ofa speed controller according to a preferred embodiment of the invention;and

FIG. 5 is a magnified view showing a portion of a speed controlleraccording to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 3, a speed controller according to a preferableembodiment of the invention is shown. For example, the speed controlleris an SMC 1200 series speed controller or an SMC 1400 series speedcontroller. Referring to FIG. 4, there is shown a rotary button of thespeed control according to the invention. Furthermore, FIG. 5 is amagnified view showing a portion of the speed controller.

The speed controller 30 includes a housing 34 and a controller body 32partly inserted in the housing 34. The controller body 30 has a rotarybutton 36 located at one end thereof and outside the housing 34. Therotary button 36 has no stripes thereon, but has a slot 38, such as anelongated slot, on the top surface thereof as shown in FIG. 4. Therotary button 36 can be rotated by using a tip-elongated screwdriver toengage the elongated slot 38, thereby adjusting an amount of aphotoresist liquid sprayed. The slot 38 can also be a crossed slot.Under this condition, the rotary button 36 can be rotated by using atip-crossed screwdriver. Furthermore, an indicator 40, such as an arrow,is located at one end of the slot 38 for indicating how many turns therotary button 36 has been rotated.

It is noted that the speed controller 30 further includes a transparenttube 42 which is used to enclose the rotary button 36. The outsidesurface of the transparent tube 42 has a vertical scale with scales, 0,1, 2, 3, . . . while the top circumference of the transparent tube 42has a circular scale with scales, 0, 1/8,, 1/4, . . . as shown in FIG.5. The position of the rotary button 36 can be determined by reading thevertical scale and the circular scale. Since the rotary button 36 isenclosed by the transparent tube 42, and a screwdriver must be used toadjust the rotary button 36, the rotary button 36 cannot beunintentionally adjusted or contacted. Therefore, it is unnecessary toinstall an additional fixing button 26 as stated in prior art.

As an example, the position of the rotary button 36 ascends or descendsone scale once the rotary button 36 is rotated one turn. If less thanone turn is rotated, the circular scale is added to precisely determinethe position of the rotary button 36. As shown in FIGS. 4 and 5, it canbe known that the rotary button 36 is rotated 2 and 3/8 turns.

When the speed controller 30 is applied in a real system, it can be setthat a filter must be replaced with a new one whenever the speedcontroller 30 is adjusted to a certain scale. That is, the replacementof the filter depends on the scales instead of the time as stated in theprior art, wherein the scales indicates the extent of the filtercongested. As a result, the problem stated in the prior art of forcingthe filter, which cannot function well, to be continuously used isresolved, thereby ensuring the quality of a formed photoresist. On theother hand, if photoresist is unclean or photoresist is congealed tocause the filter deteriorated, it can be shortly discovered that thespeed controller 30 has been abnormally adjusted. Even which photoresistbottle to cause the problem or which date the problem is caused can befound for eliminating the root cause.

Moreover, if the deterioration of the system, such as the filter, isinevitable, each time the speed controller should be adjusted within asmall range. However, if the traditional speed controller is used, thedifference between the amounts thereof adjusted in the last time and thenext time cannot be known owing to lack of scales. In contrast, if thespeed controller according to the invention is used, the vertical andcircular scales can be recorded for each check. Sometimes an abnormalityis encountered. For example, in general, only one scale is required tobe adjusted to reach a standard amount sprayed, but why it is requiredto adjust 7 scales today. At this time, this problem can be shortlydiscovered, and then resolved. Furthermore, the speed controller of theinvention is suitable for a long-term follow.

In summary, the speed controller with scales according to the inventionhas the following advantages.

(1) the deterioration of the system can be previously discovered.

(2) The extent of deterioration of the system can be determined byreading the scales, thereby increasing yield.

(3) The rotary button can be precisely adjusted.

(4) It is convenient for engineering analysis.

While the invention has been described by way of example and in terms ofthe preferred embodiment, it is to be understood that the invention isnot limited to the disclosed embodiment. To the contrary, it is intendedto cover various modifications and similar arrangements as would beapparent to those skilled in the art. Therefore, the scope of theappended claims should be accorded the broadest interpretation so as toencompass all such modifications and similar arrangements.

What is claimed is:
 1. A speed controller with scales, used to adjustthe amount of an air flow thereby to control the amount of a chemicalliquid sprayed, the speed controller comprising:a housing; a controllerbody partly inserted in the housing and having a rotary button which islocated at one end thereof and outside the housing, wherein the rotarybutton has a slot and an indicator thereon, and the indicator is locatedat one end of the slot; and a transparent tube enclosing the rotarybutton, which has a vertical scale on the side thereof and a circularscale on the top circumference thereof.
 2. The speed controller asrecited in claim 1, wherein the speed controller comprises an SMC 1200series speed controller.
 3. The speed controller as recited in claim 1,wherein the speed controller comprises an SMC 1400 series speedcontroller.
 4. The speed controller as recited in claim 1, wherein therotary button has no stripes thereon.
 5. The speed controller as recitedin claim 1, wherein the slot is an elongated slot.
 6. The speedcontroller as recited in claim 5, wherein the rotary button is rotatedby using a tip-elongated screwdriver to engage the elongated slotthereby to adjust the amount of a chemical liquid sprayed.
 7. The speedcontroller as recited in claim 1, wherein the slot is a crossed slot. 8.The speed controller as recited in claim 7, wherein the rotary button isrotated by using a tip-crossed screwdriver to engage the crossed slotthereby to adjust the amount of a chemical liquid sprayed.
 9. The speedcontroller as recited in claim 1, wherein the position of the rotarybutton is determined by reading the circular scale and the verticalscale.
 10. The speed controller as recited in claim 1, wherein theindicator is an arrow.
 11. The speed controller as recited in claim 1,wherein the chemical liquid is a photoresist liquid.